When you transform the keys to lowercase for a case-insensitive lookup, keep the old name around for printing later. 
#! /usr/bin/perl

%hash1 = ("John", 43, "Paul", 25, "Marie", 22);
%hash2 = ("john", 43, "Paul", 25, "marie", 22); 

my %lc_hash1 = map { lc $_ => { name => $_,
                                value => $hash1{$_} } 
                   } keys %hash1;

while (($KEY_2, $VALUE_2) = each %hash2){
    if (exists $lc_hash1{lc $KEY_2}){
         print "$KEY_2 : Matched\n";
    }
    else{
         print "$KEY_2 : Did not match\n";
    }
}

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Now you can use $lc_hash1{$SOMEKEY}{name} for the original key and $lc_hash1{$SOMEKEY}{value} for the value.

In reply to Re: Ignore Case when comparing Hash Keys by ctilmes
in thread Ignore Case when comparing Hash Keys by avidcoder

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